Small-scale, concentrating, solar CHP system

Abstract

A high-efficiency, small-scale, combined heat and power, concentrating solar energy system (200), designed specifically for residential and other relatively low-power applications, rendering it cost-effective and economically viable. Two-axis tracking of a dish-like reflector (10) of between 1 and 2 meters in aperture ensures very high concentrating ratios of between 200 and 8-suns or even higher. In consequence very high coolant outlet temperatures, of 120-180° C. may be reached at the outlet of the collector coolant, which may be oil, gas, or pressurized water. The high coolant temperatures are advantageous because they may be used for air-conditioning. The high concentration is advantageous because the efficiency of the photo_voltaic cells is improved with higher concentration. The overall efficiency is greater than 60%. Additionally, a simple but accurate drive, designed as a radio-dial drive (14), with substantially zero backlash, and substantially zero drive, is provided for driving the concentrating solar energy system. Preferably, two radio-dial drives are employed and tracking is performed along two axes, of an azimuth-elevation mount, a polar mount, or a cross mount.

1. A solar power system comprising:
 at least one device, each said device including a single solar radiation concentrator having an aperture of between about 0.5 m and about 2 meters, adapted for focusing incident solar radiation, said solar radiation concentrator configured to achieve at least 200 suns concentrating ratio; 
 at least one power conversion unit which receives said light after being focused; and 
 at least one solar tracking apparatus comprising at least one rotational drive. 
 
     
     
       2. The system according to  claim 1 , wherein the system is configured for generating electric power and heat. 
     
     
       3. The system according to  claim 1 , wherein the system is configured for generating electric power. 
     
     
       4. The system according to  claim 1 , wherein the system is configured for generating heat. 
     
     
       5. The system according to  claim 1 , wherein said solar radiation concentrator is shaped as a concave parabolic dish with diameter of about 1.1 meters. 
     
     
       6. The system according to  claim 1 , wherein the solar radiation concentrator is shaped as a dish or a polygon. 
     
     
       7. The system according to  claim 1 , wherein said at least one rotational drive comprises a radio-dial type drive. 
     
     
       8. The system according to  claim 7 , wherein said radio-dial type drive is configured to have substantially zero backlash. 
     
     
       9. The system according to  claim 7 , wherein said radio-dial type drive is configured to have substantially zero drift. 
     
     
       10. The system according to  claim 7 , wherein said radio-dial type drive comprises a cable wrapped about a rotational element under a tension sufficient to have substantially zero backlash and substantially zero drift to avoid slack and slippage between the cable and the rotational element. 
     
     
       11. The system according to  claim 1 , wherein the tracking apparatus comprises two rotational drives rotating around two non-parallel rotation axes. 
     
     
       12. The system according to  claim 1 , further comprising a controller configured to maximize the radiation flux on the power conversion unit, using at least one of (a) a calculated expression based on geographical and time data, (b) a closed loop correction based on a measurement of at least one of the radiation flux or the generated output power. 
     
     
       13. The system according to  claim 1  wherein the solar radiation concentrator is configured to concentrate to at least about 800 suns. 
     
     
       14. The system according to  claim 1 , wherein the power conversion unit comprises at least one of a thermal engine and one or more concentrated photovoltaic cell. 
     
     
       15. The system according to  claim 2 , characterized by a combined conversion efficiency to heat and electricity of at least 60%. 
     
     
       16. The system according to  claim 15 , wherein the combined conversion efficiency is about 80%. 
     
     
       17. The system according to  claim 1 , further comprising a coolant fluid mechanism adapted to heat the coolant fluid to at least 120° C. by absorbing heat from the power conversion unit. 
     
     
       18. The system according to  claim 17 , wherein the coolant fluid mechanism is adapted to heat the coolant fluid to at least 180° C. 
     
     
       19. The system according to  claim 1 , wherein said at least one device and said at least one power conversion unit comprise a plurality of solar radiation concentrators and a plurality of power conversion units configured to be installed on a single said solar tracking apparatus. 
     
     
       20. A solar plant comprising one or more solar collectors, wherein at least one of said solar collectors comprises:
 at least one device, each said device including a single solar radiation concentrator having a diameter smaller than about 2 meters with at least 200 suns concentration, adapted for focusing incident solar radiation; 
 at least one power conversion unit which receives said light after being focused; and 
 a solar tracking apparatus comprising at least one rotational drive. 
 
     
     
       21. A solar plant according to  claim 20 , wherein said one or more collectors comprises a plurality of collectors which share a fluid pathway. 
     
     
       22. The solar plant according to  claim 20 , further comprising a controller, which controls at least one solar tracking apparatus. 
     
     
       23. The solar plant according to  claim 21 , wherein said one or more solar collectors further comprising a coolant fluid mechanism, and wherein said fluid pathway comprises a common closed loop coolant system. 
     
     
       24. The solar plant according to  claim 23 , wherein said closed-loop coolant system comprises at least one heat exchanger. 
     
     
       25. A method for supplying energy, the method comprising:
 providing at least one device, each said device including a single solar collector, comprising:
 a single solar radiation concentrator having a diameter smaller than about 2 meters, adapted for focusing incident solar radiation; 
 at least one power conversion unit which receives said light after being focused; and 
 a solar tracking apparatus comprising at least one rotational drive; and 
 
 supplying at least one of a hot fluid and electric power to one or both of at least one appliance, and at least one power grid or both, using the at least one device. 
 
     
     
       26. The method according to  claim 25 , wherein the at least one appliance comprises a space heater comprising a heat exchanger. 
     
     
       27. The method according to  claim 25 , wherein the at least one appliance comprises an air conditioner comprising at least one absorption chiller. 
     
     
       28. The method according to  claim 25 , wherein the at least one appliance comprises a hot water supply comprising a heat exchanger. 
     
     
       29. The method according to  claim 25 , wherein the at least one appliance comprises a plurality of appliances, and wherein the supplying of the hot fluid comprises supplying the hot fluid at substantially different temperatures to each of at least two of the plurality of appliances. 
     
     
       30. The method according to  claim 25 , further comprising discarding excess heat. 
     
     
       31. The method according to  claim 25 , further comprising transmitting electric power to an electric grid. 
     
     
       32. The system according to  claim 1 , wherein each said concentrator has a single focal point. 
     
     
       33. The system according to  claim 32 , wherein each of said at least one power conversion unit is positioned substantially at said focal point. 
     
     
       34. The system according to  claim 33 , wherein each said concentrator has a dish-like configuration. 
     
     
       35. The system according to  claim 33 , wherein each said concentrator has a polygonal configuration. 
     
     
       36. The system according to  claim 1 , wherein each said concentrator has a focal line. 
     
     
       37. The system according to  claim 36 , wherein each said concentrator has a trough-like configuration. 
     
     
       38. The solar plant according to  claim 20 , wherein each said solar radiation concentrator has up to 800 suns concentration.